9 - x^2 + 2xy -y^2
giải hpt:
\(\hept{\begin{cases}x+\frac{2xy}{\sqrt[3]{x^2-2x+9}}=x^2+y\\y+\frac{2xy}{\sqrt[3]{y^2-2y+9}}=y^2+x\end{cases}}\)
EZ game
Xét x=y=0
Xét x và y khác 0
Cộng từng vế hai phương trình
Đánh giá VP >= VT
rút gọn biểu thức
a)(x+3)(X^2-3x+9)-(54+x^3)
b)(2x+y)(4x^2-2xy+y^2)-(2x-y)(4x^2+2xy+y^2)
a) (x+3)(x^2-3x+9)-(54+x^3)
= x^3- 3x^2+9x+3x^2-9x+27-54-x63
= -27
b) (2x + y)(4x^2 – 2xy + y^2) – (2x – y)(4x^2+ 2xy + y^2)
= (2x + y)[(2x)^2 – 2x.y + y^2] – (2x – y)[(2x)^2 + 2x.y + y^2]
= [(2x)3^3+ y^3] – [(2x)^3 – y^3]
= (2x)^3 + y^3 – (2x)^3 + y^3
= 2y^3
a)(x+3)(X^2-3x+9)-(54+x^3)
= \(x^3\)+ \(3^3 \) - 54 -\(x^3\)
= 27- 54
= -27
b)(2x+y)(4x^2-2xy+y^2)-(2x-y)(4x^2+2xy+y^2)
= \((2x)^3\) + \(y^3\) - [\((2x)^3\) - \(y^3\) ]
= \(8x^3\) + \(y^3\) - \(8x^3\) + \(y^3\)
= \(2y^3\)
a) Ta có: \(\left(x+3\right)\left(x^2-3x+9\right)-\left(54+x^3\right)\)
\(=x^3+27-54-x^3\)
=-27
phân tích ĐT sau thành nhân tử
a)x^2-2xy+y^2-1
b)9-x^2-2xy-y^2
c)25-x^2+4xy-4y^2
a) \(x^2-2xy+y^2-1=\left(x-y\right)^2-1=\left(x-y-1\right)\left(x-y+1\right)\)
b) \(9-x^2-2xy-y^2=9-\left(x^2+2xy+y^2\right)=9-\left(x+y\right)^2=\left(3-x-y\right)\left(3+x+y\right)\)
c) \(25-x^2+4xy-4y^2=25-\left(x^2-4xy+4y^2\right)=25-\left(x-2y\right)^2=\left(5-x+2y\right)\left(5+x-2y\right)\)
a. x2 - 2xy + y2 - 1
= (x - y)2 - 12
= (x - y - 1)(x - y + 1)
b. 9 - x2 - 2xy - y2
= 32 - (x + y)2
= (3 - x - y)(3 + x + y)
c. 25 - x2 + 4xy - 4y2
= 52 - \(\left[x^2-4xy+\left(2y\right)^2\right]\)
= 52 - (x - 2y)2
= (5 - x + 2y)(5 + x - 2y)
Giải hệ phương trình: \(\left\{{}\begin{matrix}x+\dfrac{2xy}{\sqrt[3]{x^2-2x+9}}=x^2+y\\y+\dfrac{2xy}{\sqrt[3]{y^2-2y+9}}=y^2+x\end{matrix}\right.\)
Tìm x,y để x2+2xy+y2=9 và x2-2xy+y2=1
x2+2xy+y2=9
=>(x2+xy)+(xy+y2)=9
=>x(x+y)+y(x+y)=9
=>(x+y)(x+y)=3.3
=>x+y=3
x2-2xy+y2=1
=>(x2-xy)+(y2-xy)=1
=>x(x-y)+y(y-x)=1
=>x(x-y)-y(x-y)=1
=>(x-y)(x-y)=1.1
=>x-y=1
x+y+x-y=3+1
=>2x=4
=>x=2
=>y=2-1
=>y=1
vậy x=2 và y=1
(x+2)^2-2x(x+1)+(x-3)(x+3)
(x+2y)(x^2-2xy+4y^2)-(x-2y)(x^2+2xy+4y^2)+2y^3
(3+x)(x^2-9)-(x-3)(x^2+3x+9)
(x-y)^3-(x-y)(x^2+xy+y^2)
\(\left\{{}\begin{matrix}x+\frac{2xy}{\sqrt[3]{x^2-2x+9y}}=x^2+y\\y+\frac{2xy}{\sqrt[3]{y^2-2y+9}}=y^2+x\end{matrix}\right.\)
rút gọn các biểu thức sau:
a) (x+3).(x^2-3x+9)-(54+x^3)
b)(2x+y).(4x^2-2xy+y^2)-(2x-y).(4x^2+2xy+y^2)
b) \(\left(2x+y\right)\left(4x^2-2xy+y^2\right)-\left(2x-y\right)\left(4x^2+2xy+y^2\right)\)
\(=\left(2x+y\right)\left(4x^2-2xy+y^2\right)+\left(2x+y\right)\left(4x^2+2xy+y^2\right)\)
\(=\left(2x+y\right)\left(4x^2-2xy+y^2+4x^2+2xy+y^2\right)\)
\(=\left(2x+y\right)\left(8x^2+2y^2\right)\)
\(=\left(2x+y\right)\left(4x+y\right).2xy\)
a,3xy+x+15y+5
b,9-x^2-2xy-y^2
c,x^3-5x^2+x-5
d,x^2+y^2-2xy-1
tìm x
(5x-1)=(1-5x)^2
9-(x-2)^2=0
a. \(3xy+x+15y+15=x\left(3y+1\right)+15\left(y+1\right)=\left(x+15\right)\left(3y+1\right)\)
b.\(9-x^2-2xy-y^2=9-\left(x+y\right)^2=\left(3+x+y\right)\left(3-x-y\right)\)
c.\(x^3-5x^2+x-5=x^2\left(x-5\right)+\left(x-5\right)=\left(x^2+1\right)\left(x-5\right)\)
d.\(x^2-2xy+y^2-1=\left(x-y\right)^2-1=\left(x-y+1\right)\left(x-y-1\right)\)
\(\left(5x-1\right)=\left(1-5x\right)^2\)
\(\left(5x-1\right)=\left(5x-1\right)^2\)
\(\left(5x-1\right)\left(1-5x+1\right)=0\)
\(\left(5x-1\right)\left(2-5x\right)=0\)
\(\left[\begin{array}{nghiempt}x=\frac{1}{5}\\x=\frac{2}{5}\end{array}\right.\)
\(9-\left(x-2\right)^2=0\)
\(\left(3+x-2\right)\left(3-x+2\right)=0\)
\(\left(1+x\right)\left(5-x\right)=0\)
\(\left[\begin{array}{nghiempt}x=-1\\x=5\end{array}\right.\)
a,3xy+x+15y+5
b,9-x^2-2xy-y^2
c,x^3-5x^2+x-5
d,x^2+y^2-2xy-1
tìm x
(5x-1)=(1-5x)^2
9-(x-2)^2=0